The present invention relates to an excavating tooth assembly generally, and more particularly to an assembly that includes a resilient member for securing an excavating tooth in a holder.
U.S. Pat. Nos. 2,968,880 and 3,323,236 to Peterson disclose excavating tooth assemblies including a tooth having a tapered distal end for digging and a proximal end having laterally spaced prongs which are secured in a recess of a shank or tooth holder by a resilient retainer. The resilient retainer is generally positioned between the tooth prongs and portions of the tooth holder that are adjacent to the prongs to frictionally secure the tooth in the tooth holder. In U.S. Pat. No. 2,968,880, an excavating tooth formed with two laterally spaced prongs is received in a recess formed in a tooth holder. A web, extending vertically in the recess, fits in the space formed between the two prongs. Before the prongs are positioned about the web, a resilient retainer (preferably circular in cross-section) is passed through a transverse hole in the web to be pushed backwardly and against the outer walls of the web as the tooth prongs are inserted into the tooth holder. In this manner, the resilient retainer is compressed between the vertical outer walls of the web and the inner vertical surfaces of the tooth prongs to secure the tooth to the tooth holder.
In U.S. Pat. No. 3,323,236, the resilient member is located and positioned in a different manner to enhance the area of surface contact between the resilient retainer and the surfaces between which it is compressed to more securely hold the tooth in the holder. The holder includes top and bottom flanges between which the tooth prongs are inserted. Before the prongs are inserted into the tooth holder, the resilient member is bent in a U-shape and the ends thereof inserted into a pair of downwardly-rearwardly directed holes formed through either the top or bottom flange. When the tooth is forced into the recess formed between the spaced top and bottom flanges of the holder, the internal ends of the resilient retainer are compressed between the prongs and the inner surface of the flange through which the retainer extends to secure the tooth to the holder. In one embodiment, grooves are provided in the inner surface of the flange to receive the retainer ends. The cross-sectional shape of each groove, in which the retainer is seated, preferably is substantially different from the initial unstressed shape of the resilient retainer such that a considerable deformation of the retainer occurs when under compression. This deformation increases the area of surface contact between the retainer and the tooth and tooth holder. Among the drawbacks of this design is that a substantial portion of the retainer extends between the two holes on the outside of tooth holder. Although a groove can be formed in the outside of the holder to seat this portion in a recess, this portion remains exposed to the environment. Such exposure can lead to reduced retainer life when the assembly is subjected to abrasive materials, for example.